By JOSEPH BERGER and AL BAKER; Noah Rosenberg contributed reporting.

Published: July 21, 2011

Leiby Kletzky, the 8-year-old boy who was killed last week after being kidnapped as he walked home alone from day camp, was drugged with painkillers and muscle relaxants before he was smothered to death, the city medical examiner's office announced on Wednesday.

A statement by Dr. Charles S. Hirsch, the chief medical examiner, said the cause of death was not just suffocation, but also ''intoxication by the combined effects of cyclobenzaprine (muscle relaxant), quetiapine (antipsychotic), hydrocodone (pain medication), and acetaminophen (Tylenol).''

The findings added another grim twist to a case that has transfixed New York, devastated the Orthodox community of Borough Park, Brooklyn, and prompted parents to wonder about how lenient they should be in letting their children walk the streets alone. Leiby was abducted on July 11 after asking his parents if they could trust him to walk seven blocks from his camp to meet them. He was killed the next day, and his body was dismembered.

A Brooklyn grand jury late Wednesday indicted Levi Aron, a 35-year-old hardware store clerk, on eight counts of murder and kidnapping, which carry a maximum sentence of life imprisonment without the possibility of parole. The Brooklyn district attorney, Charles J. Hynes, said his office had received no evidence that Leiby was sexually abused during his captivity.

The police had said that Leiby was suffocated with a towel inside Mr. Aron's attic apartment in nearby Kensington, basing their account on what Mr. Aron told them in a statement. Mr. Aron was apparently in Borough Park to pay a dentist's bill and, according to the police, was asked by Leiby for help with finding his way home. He offered to drive Leiby in his brown 1990 Honda, and security cameras recorded Leiby entering the car.

Mr. Hynes, at a news conference, said the drugs had been administered orally, which he said could be used as proof of an intention to kill. He said ligature marks on the boy's wrists ''would indicate that at some point he was tied up.''

Hydrocodone is popularly sold as Vicodin, a commonly abused prescription opiate, and quetiapine appears under the brand name Seroquel. Mr. Aron's use of Seroquel would dovetail with a statement by his lawyer, Pierre Bazile, made when Mr. Aron pleaded not guilty, that Mr. Aron ''has indicated to me that he hears voices and has had some hallucinations.''

Police officials said Wednesday that they had already been investigating the possibility that Leiby had been drugged because they found prescription pills in Mr. Aron's name inside his apartment.

The police also said Wednesday that they had ''documentary evidence'' confirming one of the odder aspects of the case -- Mr. Aron's tale of how on July 11, he took the boy to a relative's wedding at a Rockland County, N.Y., catering hall some 35 miles northward in Spring Valley, just outside the largely Hasidic village of New Square. Mr. Aron told the police that the boy sat in the car with the windows rolled down while he went inside the Ateres Charna hall, where 400 people were celebrating the wedding.

Izzy Goldstein, manager of Ateres Charna, said he did not remember seeing Mr. Aron or the boy at the wedding. But Mr. Goldstein disclosed that police officials had downloaded the digitized record from the wedding hall's security cameras and took the discs with them to New York. The boy was seen by a gas station attendant during the trip, Mr. Hynes said.

The police also said Leiby was killed sometime late Tuesday afternoon or early that evening. Investigators now believe that the portion of his remains that were discovered inside a suitcase in a Dumpster had been deposited by the suspect after midnight that Tuesday, shortly before investigators went to his home at 2:40 a.m. Wednesday.

Assemblyman Dov Hikind, who represents Borough Park, said in an interview that Leiby's grandparents, Yitzchok and Mirel Forster, had told him that the family was afraid that Mr. Aron would find a way to go free on an insanity defense. But, typically, defendants who are found not guilty of murder by reason of insanity spend years in locked psychiatric wards.

Meanwhile, a special prayer service was held Wednesday night at Congregation Anshe Sfard in Borough Park, hours after Leiby's parents, Nachman and Itta Kletzky, finished sitting shiva. Members of the Kletzky family were expected to attend.

PHOTO: A memorial service for Leiby Kletzky was held on Wednesday at Congregation Anshe Sfard. Earlier in the day, Levi Aron was charged with eight counts of murder and kidnapping in Leiby's death. (PHOTOGRAPH BY TY CACEK/THE NEW YORK TIMES)